Once a person has learnt full OLL and PLL, how can they improve? Speedcubers like Yiheng only know the basics just like us but they're still a lot faster than us. How? What's the thing that they do and we don't?
I’m pretty sure YiHeng has to perform hundreds of solves every day, therefore significantly increasing his lookahead abilities. I’m not sure what he knows beyond OLL and PLL, though. Someone else may be able to clarify that.